How do you know when your start to have an orgasum?

Answer 1

You will know when a girl has an orgasm when you can feel her vaginal muscles contract a little and her legs and thighs will tighten, also her vagina will start getting wetter and she will start to sweat and her breathing will become increasingly rapid along with her heart rate.

A wave of pleasure with intense muscle contractions "down there" in particular and usually you'll get very wet too. If you're not sure then keep going until you are! There is no harm in it.

If you're a guy, you'll know you have if your hand is covered in sticky stuff.

Answer 2

For females:

A series of involuntary rhythmic rapid muscle contractions and spasms that start in the pelvic area and can spread to other parts of the body where muscles tighten, vaginal fluids enhance and your breathing quickens and intense tingling ensues.